Roll-over is a type of accident, fatal in many cases, frequently suffered by tractor drivers when driving over rough terrain, on the sides of slopes, ditches, etc. To reduce the number of accidents some devices have been developed, apart from fixed protective structures, to ensure that the driver is protected when the tractor rolls over.
Patent US2007/0182147 can be mentioned in this respect, which describes a frame with two articulated lateral sides mounted on a support attached to the tractor itself, and with a number of elastic elements that allow the folding and unfolding of the structure.
The structure in that patent is intended to be fitted to the back of the driver's seat, which means that in some cases the driver is not completely protected on roll over, regardless of the complex structure and possible failures in the folding and unfolding operations. Furthermore, it does not offer an automatic activation that guarantees its operation independently of the driver's wish.
Nor is such automatic operation included in the anti-rollover protection system described in patent European EP870298, thus limiting its action to passive protection, considering its location behind the driver's seat.
Patent US2004/0145172 can also be mentioned, having similar characteristics to those described above, being fitted with a structure intended preferably for vehicles equipped with shovel and excavator. In this patent, however, the protective structure is even more complex than the previous instances though without solving their problems.
In European patent EP0500261, on the other hand, the structure consists of two articulated sections, one attached to the vehicle structure or frame and the other telescopic part protrudes from the first section and is capable of being automatically deployed in the case of rollover, but without changing the geometry so the maximum width remains the same.
Swiss patent CH559646 describes an anti-roll over device made up of a “V” shaped structure closed at the top that can be adapted to different vehicles due to the telescopic nature of the upper horizontal section, but with manual activation and fastening to adapt its width to that of the vehicle, while keeping its shape and only acting as a static protection element.
The rollover protection device described in patent document WO0204259 is retractable, consisting of an inverted “U” shaped arch with telescopic vertical tubes and a horizontal bar which is deployed when rollover is imminent by means of a sensor activated when the dowels that hold the deployable bars are freed by pneumatically triggering the action of springs which, in turn, push the telescopic bars, moving them vertically without increasing the width of the structure when deployed.
Similarly, the device designed for individual protection described in patent publication US2010171296 consists of an inverted “U” structure arranged in such a way as to be activated when sensors detect a rollover, propelling the protection bar by using gas to cause a wholly vertical deployment. As in the previous case, it does so without increasing the width of the structure.
None of the structures referred to above completely solve the problem arising from a tractor or similar vehicle rolling over, regardless of the complexity of their construction. More importantly, in most of them, the folding and unfolding motions require mechanical articulation elements which, undoubtedly, give rise to extra stress and possible trapping of the driver, except for patents EP0500261, WO0204259 and US2010171296, whose automatic action relies on mechanical elements that require a high level of maintenance, all of them offering limited protection since there is no horizontal deployment in the upper part of the structure.